Acrobat 9 Issue: Show alert when field is empty

A setFocus() action is a bit of a tricky thing to put into an OnBlur event. You have real potential for an infinate loop and that's exactly what's happening. The code sets focus back into the field and then displaying the alert box, which removes focus from the field, queing up another OnBlur event.

In Acrobat 8 the timing is a bit different so that the focus is set back to the field after the alert returns. And that of course is the solution, move the setFocus() after the alert.

There are a couple of other things that are not quite right with this script. First, the getField line is redundant. The field is already in the event object, i.e, event.target. The script should look like this.

Second, the script itself, while it works, falls a ways outside of best practices. Field validation should be done in two places, in the Validate event and at submission time.

Thom Parker
The source for PDF Scripting Info
[url=http://www.pdfScripting.com]pdfscripting.com[/url]

The Acrobat JavaScript Reference, Use it Early and Often
[url=http://www.adobe.com/devnet/acrobat/javascript.php]http://www.adobe.com/devnet/acrobat/javascript.php[/url]

Thanks, that seemed to work under the onBlur action. Out of curiousity, do I need to alter the code in order to place it as a validation script? I used the code as-is and it didn't seem to do anything.

Yes, the code needs to be modified to work in a validation script. In a validate event the new field value is stored in "event.value". This is covered in the Acrobat JavaScript Reference, the Acrobat JavaScript Guide, there's an article on it in the tutorials on this site, and there are video tutorials, scirpt samples, and demo files that cover this issue ad-nauseum at www.pdfscripting.com. Take a look at any of these.

The validation script is only called when data is entered into the field. That's why null testing (i.e. empty testing) is done at submit time.


Thom Parker
The source for PDF Scripting Info
[url=http://www.pdfScripting.com]pdfscripting.com[/url]

The Acrobat JavaScript Reference, Use it Early and Often
[url=http://www.adobe.com/devnet/acrobat/javascript.php]http://www.adobe.com/devnet/acrobat/javascript.php[/url]